This invention relates generally to a method and apparatus for applying solder flux onto a pretinned work surface, and more particularly, to a method and apparatus for applying a uniform film of flux to a solder work surface by dispensing flux into a perforated chamber surrounded by a thermode reflow device and heating the chamber until vaporized flux is forced onto the work surface.
There are several known techniques for applying flux in fine pitch thermal reflow processes. In some cases, a syringe containing the flux is attached to a manual or pneumatic dispenser. Unfortunately, such syringes are often difficult to handle and use, and the flux is not dispensed so as to produce a uniform film. Thus, not only does the volume of flux dispensed vary, but the wetting area also varies. In addition, the dispensing apparatus must be continually inspected to detect clogging.
In other cases, flux is brushed onto the solder work surface. In addition to suffering from some of the problems associated with syringes (i.e. volume and wetting area variation), flux being brushed can drip onto the work surface. Further, the brushes are easily contaminated.
Spraying is another technique for depositing flux on solder work surfaces. The spraying equipment itself, however, is very costly and requires a great deal of maintenance.
Thus, what is required is a reliable and inexpensive technique for applying flux onto a solder work surface.